At present, universal serial bus (USB) is the most popular transmission interface for computer peripherals and was developed and promoted by Intel and Microsoft and gone through the development process of three versions, respectively: USB 1.0, USB 1.1 and USB 2.0. The standards of USB 1.0, 1.1 and 2.0 support the following three transmission rates: (1) a low-speed transmission rate of 1.5 Mbps; (2) a full-speed transmission rate of 12 Mbps; and (3) a high-speed transmission rate of 480 Mbps.
As the electronic industry advances, even the transmission rate of the USB 2.0 can no longer meets the industrial and user requirements, so that the other USB 3.0 standard is introduced. In the USB 3.0 standard, two sets of differential terminals and a grounding terminal are added to the USB 2.0 having four terminals, so that the USB 3.0 standard has a total of nine terminals, and the transmission rate can reach up to the level of 5 Gbps.
Based on the prior art, a female connector in compliance with the USB 3.0 standard comprises an insulating body, a tongue plate extended from a front end of the insulating body for installing a contact portion of the five added terminals and a contact portion of the original four terminals of the USB 2.0 standard on opposite surfaces of the tongue plate respectively. Since the positions of these terminals are standardized, therefore the five added terminals and the original four terminals can be arranged in two rows in the vertical direction, and all terminals are separated from each other to avoid short circuits.
However, computer peripherals and their corresponding connectors tend to be developed with an increasingly thinner, lighter, shorter and smaller design, so that the level of difficulty for installing the nine terminals on the small-size tongue plate is increased significantly and the total volume of the connector cannot be decreased further.
It is a subject for related manufacturers to overcome the aforementioned problems, so that the inventor of the present invention conducted extensive researches and experiments, and finally provided a feasible design to overcome the problems.